Radiation transporting devices provided with hollow members mounted in an array



Sept. 3, 1968 E. E. SHELDON 3,400,292

RADIATION TRANSPORTING DEVICES PROVIDED WITH HOLLOW MEMBERS MOUNTED 1N AN ARRAY Original Filed Jan. 2?, 1965 5 Sheets-Sheet l btie@ M O 5 m M wm f N` 1M A M MM F ai, 0 /v u l w "MMI: u l, E V/\ .Q k N Q n. sw M. n* d\` d@ m .ru

Sp. 3, 1968 E, E, SHELDON 3,400,292

RADIATION TRANSPORTING DEVICES PROVIDED WITH HOLLOW MEMBERS MOUNTED IN AN ARRAY Original Filed Jan. 27, 1965 5 Sheets-Sheet 2 mm1: 5mm! www :wmf

Spt. 3, 1968 E, E SHELDON 3,400,292

RADIATION TRANSPORTING DEVICES PROVIDED WITH HOLLOW MEMBERS MOUNTED IN AN ARRAY Original Filed Jan. 27, 1965 5 Sheets-Sheet 5 www IBM

INVENTOR. Eh/A/ EMM/JEL SHE-Lamy an l hoshimi RADIAIIUN TRANSPORTING DEVICES FRU- VIDED WITH HOLLW MEMBERS MOUNTED IN Alti ARRAY Edward Emanuel Sheldon, E. 40th St.,

. New York, 10016 @riginal application Ilan. 27, 1965, Ser. No. 428,483, now 'Patent No, 3,305,690, dated Feb. Z1, 1967. Divided and this application Oct. 2li, 1965, Ser. No. 498,961

I7 Claims (Ci. 313-6S) @mamma-:ummm

This invention relates to the novel instrument for examination of the interior of the parts, channels or passages which are inaccessible to the examiner and is a division ot' my copending application Ser. No. 428,483, filed Ian. 27, i965 'and which is now U.S. Patent 3,305,690, dated Feb. 21, 1967 and having the original filing date of Mar. ll, 1954 through divisional applica tion Ser. No. 170,745, led Feb. 2, 1962, now Patent No. 3,205,390, dated Sept. 7, 1965, which is a division of Ser, No. 785,849, filed Jan. 9, 1959, now Patent No. 3,027,477, dated Mar. 27, 1962, which in turn is la division of Ser. No. 415,699, tiled Mar. 11, 1954, now Patent No. 2,877,368, dated Mar. l0, 1959. Due to the inability of light to see around the corners, the present instruments used for such examination have to be straight and rigid so that the eye of the examiner and the examined part are in one straight line. The instruments using optical lenses or prisms will not help in the situation when the shape and the size of the examined part is variable and 'unknown in. advance. In such a Case, the position of the curves and angulations in the examined parts or passages is unknown and therefore the lenses or prisms cannot be positioned to anticipate deviations of the axis of the examined channel from the straight line.

The purpose of this invention is to provide means for inspection of inaccessible channels, such as hollow parts of machinery or of other` inaccessible tortuous passages. My device may 'be introduced inside of a part: which cannot be inspected visually without dismantling or destroying the whole machine and will transmit the image of said part to the observer outside of said part. My invention will be especially useful for the examination of coils and pipes or other curved structures. My device can also be used as a probe to be inserted into a solid object and to transmit information about its internal struc ture..

Another object of my invention is to intensify the irnage of the examined internal parts or passages so that the final image will be presented to the observer with the luminosity facilitating inspection of said image.

Another purpose of my invention is to enable simultaneous observation of said inaccessible parts by many examiners, situated in close or remote locations, -which was not possible until now.

Another object of this invention is to change, decrease or amplify the contra-st of the image of the examined bart.

The obiectives of my invention were realized by a novel Patented Sept.. di, itiiilli device which is flexible to allow its introduction into the examined part regardless of its curvatures or angulations and which after its introduction into the examined parl. will produce a light image of said part, will next convert said light image into video signals and will transmit said video signals outside of said part. Video signals are re converted in receivers outside of the examined part into visible images for inspection or recording. My intrascopfle device can produce black and white images, as well as multi-color images, showing faithfully or arbitrarily the colors of the examined part.

In particular this novel device makes use of a television pick-up tube consisting of two separate independent ele ments which can be introduced separately into the examined part and which after introduct1on work in co operation as a television camera. As each of these two separate elements is smaller in size than any conventional television camera can he made, this novel tele` vision camera can be introduced into locations which, because of small ssize or tortuous shape of passages leading to them, were inaccessible to the most rninia`tu1'--r ized television cameras known in the art.

Another marked improvement n my novel television camera is elimination of magnetic deflecting coils which. are bulky and occupy so much space that even a small television tube using them cannot Ibe introduced into nar row passages. The use of conventional electrostatic deflecting system results into a marked distortion of imn ages especially in pick-up tubes using the slow scan ning electron beam. These drawbacks are eliminated in my intrascope and therefore in spite of its very small size it is capable of producing images of a good definition and contrast.

In some applications even this novel` intrascope utiliz-A ing a pick-up tube divided into two separate independent elements cannot be introduced into very narrow or torto ous passages. In such cases I am `using a novel image conductor in combination Iwith my television pick-up tube The novel image conductor consists of a liexlble guide of material having a high index of refraction and critical angle of reection which prevents-the escape of the ight from said guide. The novel ima'ge conductor may be made of any desired size or sha'pe and therefore it can penetrate the most inaccessible locations and can trans mit the image therefrom to the television picloup tubr-` or `directly to the outside to thc observerr In the drawings;

FIGURE 1 represents a partially sectioned view of' the novel intrascope,`

FIGURES la, lb and 1c show a, modification ot the` intrascope;

FIGURE ld shows a intrascope with a simpliiied tele vision camera tube;

FIGURE 2 shows a combination ot light image sonductor with a television pick-up tube;

FIGURES 2a and 2b represent a modification oi' the combination comprising an image conductor and a plclr up tube;

FIGURE 3 represents a modified embodiment of my intrascope provided with image conductor;

FIGURE 3a represents a modification of my intra` scope in which image conductor is in. contact win, the. distal end ofthe intrascope;

FIGURES 4 and 5 represent a. simpliiied iuttastrope provided with a light image conductor; and

FIGURE 6 represents an embodiment of my lntrascopc provided with an image amplifying tube.

The new device which may be called the intrascope 'El is shown in FIGURE 1. The handle 2 is a hollow tub; diameter corresponding to the examined part. I'n-e han may be rigid or semiflexible or completely ilexible accord ing to the part to be examined. .At the end mi." the handle begins the flexible part 2a of the intrascope which also has width and length suitable for the size the examined part. ln case the intrascope is used for examination of .fragile parts, the part 2a must be very iiexible and pliable in order to avoid damage to the wall of the examined part. The basic feature of the material for the flexible part of the intrascope is therefore that it must be easily bent and molded by the walls of the passages in which it is being introduced., Such material may be a, suitable plastic, or rubber 26 of the type used by Davol Rubber Company of Providence, Rl.. for their gastric tubes. In case the intrascope is used for investigation of sturdy parts or of machinery the part 2a may be obviously more rigid. The flexible part 2n of the intrascope may be in such a case made ot' the stainless steel spiral sheet designed not only tor durability but also to maintain the proper degree of flexibility and elasticity. The metal spiral. is tapered to insure its uniform bending. The intrascope may be covered with an outer tubing 26a such as of neoprene. This prevents dust particles and moisture from affecting the optical and pickgup system located inside of the intrascope. At the end of the flexible part there is a semitlexible tip 3 which may be screwed on the ,flexible part and can be easily removed giving thereby access to the inner structures of the intrascope. The tip consists of a rubber conical finger and serves to facilitate the gliding of the intrascope within the examined part. In order to facilitate the introduction of the intrascope into parts which have no curves my device can be made semirigid by inserting into it a semirigid stilet. In case the intrascope used as a probe for insertion into a solid object the tip 3 should be preferably rigid and sharply pointed to be able to pierce the exam-1 ined object.

In some cases the examined part has to be distended by or tiuid insutilation prior to the examination. A, special lair pump attachment 44 and a channel. 44a in the intra scope is provided for this purpose. The channel 44a also may serve to evacuate contents of the examined part betore examination to improve visibility, The know 45 on the proximal end of the intrascope serves to indicate to the examiner the position of windows 12 and 18 of the intrascope. In some cases the layer 26 should be of a dielectric material to prevent any short circuits.

in the distal end of the iiexible part of the intrascope there is a housing box 5 containing the illumination systern 7. The box 5 may also be attached to the inner walls of the intrascope by means ot.' the brackets or may be held by springs. .It is obvious that there are many means for attachment of the box 5 which are well known in the art. All walls of the housing box S except the one facing the television picloup tube 16 are provided with windows it@ for transmission of the light from the illuminating system 7. These windows are correlated with the windows 12 in the flexible part of the intrascope which transmit the iight from rthe illuminating system to the examined part. in some cases the windows 12 may be made to extend over the circumference of the intrascope. ln some cases the 'window to transmit illumination from the light source to the examined part may also be provided in the distal end of the intrascope instead of being in its side walls, and in such case the tip may be made of transparent material or may be omitted. Windows 12 may be provided with shutters which can be controlled from. the proximal end t` the intrascope which is outside of the examined part. The illuminating system may consist of the electrical bulb 7.. The electrical bulb may be mounted inthe housing box 5 by mean-s of a socket 7a. In some cases it is adn vantageous to use the objective lens 11 between the light bulb and windovt- 12 in order to concentrate the light on one field. The lens :may be held. in position by brackets i111. The light bulb is activated by the source of electrical power 9 situated outside of the examined part. Such a source may be the commercial electrical current or battery of dry cells. The flexible electrical cable 8 leads from the socket, 7u to said outside source of electrical current;

i 9. The cable is Ia lacquered, double insulated electric wire. is covered in addition with liquid rubber and is vulcanized in order to prevent a short circuit. The housing unit 5 may he in some cases omitted and the light source may be attached to the socket 7a which is held by brackets.

In the tlexible part 2a proximally to the housing lbox 5, there is a rigid nontransparent housing compartment 14 containing the optical system 15 and the novel television pick-up tubes 16a and 16b. The housing 14 has an opening 17 in which the optical system 15 is lodged and which serves to admit the image of the examined part. This opening is correlated with windows 18 in the flexible part of the intrascope which transmit the image of the examined part. In some cases the windows 18 may be made to extend over all the circumference of the in trascope. The windows 18 may be provided with shutters operated from the proximal end of the intrascope which is external to the examined part. The housing 14 containing the television pick-up tubes 16a and 16b and thet optical system may be attached to the inner wall of the liexible part 2a of the intrascope by means of brack ets or may be held by springs 27a. As the housing box ts into the encasing holding member 26 and is held by it tightly, in some cases no `additional supporting means such as springs are necessary.

The optical system 15 may consist of 90 gable prism 20 and of lens 21. The optical system may have its own housing unit instead of being lodged in the compartment 14 and may be then introduced into the intrascope separately.

In some cases it is desirable to have a large field of vision and `at the same time to preserve the necessary magnification of the examined part. In such a case in stead of the prism 20a rotating mirror should be used. The mirror has lirst surface coating which eliminates the reflections and is activated by the magnetic solenoid placed beneath the mirror. The solenoid is connected by the elastic cable with the controls outside of the examined part and can tip the mirror from the retrograde position to the forward position giving thereby an additional field of vision without the necessity of moving the intrascope. The image of the expanded part is reflected by the mirror on the objective lens which focuses said image on the photocathode of the novel television pick-up tube 16!) described below. In case the magnification of the examined part is not necessary a large field of vision can be obtained by using the lens providing field of vision instead of the usual 45-50" The image produced by the optical system is inverted but it can be reverted to the original position either by an additional lens or electron-optically in the viewing tube. The rotating mirror may also serve to admit image either through window 18 or 18a without rotating the whole camera 16.

The housing box 14 contains the novel miniature television camera 16 which was designed to reduce to the minlmum the size of the television camera. The television pick-up tubes known previously in the art could be minia turized only to a certain degree7 which was not suthcient in certain applications as some of the examined parts and too small to allow the introduction even of the smallest conventional pick-up tube. This is true especially for the type of tubes having external dellecting coils such as of magnetic or electro-magnetic type, and in such situations., my novel camera 16 will be very suitable as it does not require any external deflecting or focusing coils at. all. The camera 16 consists of two vacuum tubes 16a and lob. The tube 16a has an electron gun 28 which pro duces an electron beam 29. The electron beam 29 is focused by electrostatic field 30. The electron-optical system for focusing the electron beam 29 may be sim-- plitied and markedly reduced in length by using the uni potential electrostatic lens instead of the usual two-lens system. The electron beam 29 is deflected by electrostatic plates 30a and 30h in two perpendicular to each other planes. The electrostatic plates are energized by signals salidas/3.

from sau/tooth generators which are situated outside of the examined part. The generators 32 are connected with electrostatic plates 30a and 30h by means of flexI ible wires. One deflecting field is produced by the horizontal deflection plates 30a and may have line frequency such as -l5,000 cycles per second, Another deflecting field is provided by the vertical deflection plates 30]; and may have field frequency such as -60 cycles. ln this way the electron beam 29 is made to scan the fluorescent screen 3l in a regular television raster. The deflection systern may be fulther simplified and miniaturized by having only horizontal deflection plates 30a. The vertical deflections 30B are eliminated and the vertical deflection of the fluorescent light spot is provided by the rotating drum 71 with plural mirrors 72 and shown in FIGURE ld. The fluoroescent screen 3l may be provided with electron transparent metallic conducting backing layer 3th such as of aluminum. The fluorescent screen 31 must be of a phosphor of -a very short persistence in order to obtain a good resolution of the image. Zn() has decay time of l microsecond and is :suitable for this purpose. Still better results may be obtained by means of' ZnS phosphor and using only ultra-violet component of its fluorescent emission which has decay time of 1,60 microsecond. ln some cases, it is preferable to make the fluorescent screen 31 of semispherical curved shape as it will improve definition of the flying light spot. The fluorescent layer 3l` may also be deposited on the supporting mesh screen instead of being deposited on the Wall of the vacuum tube. This will improve denitionof the flying light spot.

The vacuum tube 16a operates in combination with the vacuum tube 16b forming together the nove] television camera 16. The vacuum tube 1611 has a photoemissive electrode 33 which may be deposited or attached to one of the walls of said vacuum tube. In some cases it is preferz able to provide a light transparent conducting layer 33b such as or material known in the trade as Nesaf or of compounds of tin or of cadmium, on the side of said photoemissive electrode 33 facing the fluorescent screen 31. The photoemssive electrode 33 may be of CsOAg or of caesium, lithium or rubdiurn on an'timony, arsenic or bismuth, At the opposite end of the vacuum tube 16h there is provided photocathode 34 which consists of a light transparent signal plate 34a, a light transparent insulating layer 34h and of a photoemissive mosaic 34e. The signal plate 34a may be a thin transparent layer of metal or other conducting material. The insulating layer 34h may be of mica, silica, or other transparent dielectric material vand photoemissive mosaic 34C may be of CsOAg or of cesium, rubidium or lithium on anti mony, arsenic or bismuth. In some cases the photoemissive layer 3de may be, instead of a mosaic, also of continuous type. ln cases in which the electrostatic focusing field Z3 is used to focus the scanning electron beam 33a on the mosaic 34C, much better resolution will be obtained by making such mosaic of a curved semispherical shape. ln addition, the use of such spherically shaped photocathode will eliminate instability of the image which is very marked when using electrostatic fields for focusing a slow electron beam.

The light image of the examined part, is projected by the optical system, on the photocathode 34 of the 'vacuum tube 16h. The light image produces emission of photo-` electrons from the layer 34C. As a result a positive charge image having the pattern of said light image is left on the photoemissive mosaic 34C. Both vacuum tubes 16a and 16h are held in apposition to each other and in such a manner that the fluorescent screen 31 of the vacuum tube 16a is adjacent lto the photoemissive electrode 33 of the tube 16b. The scanning electron beam 29 impinging on the fluorescent screen 31 produces a light spot at each point of its impingementl The scanning illumination excites the photoemissive electrode 33 and produces thereby a fine scanning beam of photoelectrons 33a'. The photo-v electron beam 33a is the scanning type because it is produced by the scanning electron beam 29. The photoelectron beam. 33a may be further focused by electrostatic fields 23. In some cases the photoemissive electrode 33 and the mosaic 3d are disposed so close to each other that the focusing fields may be eliminated `which will further reduce the size of the vacuum tube 16h. When. the focusing fields are omitted l found that separation of electrode 33 and mosaic 34 should not exceed 0.25 rnillimeter.

In `a vacuum tube 16b instead of the photoemissive mosaic I may also use a photoconductive photocathode such as shown below in FIGURE 2b. The photoconduc tive photocathode comprises a conducting signal plate Stia which is connected to the circuit producing video signals and a photoconductive layer 34e deposited thereon as shown in FIGURE 2b. The photoconductive layer may be of selenium, zinc selenide or of antimony sulfide or of other photoconducting materials.

Another important modification of the vacuum tube 16]) was accomplished by eliminating the photoemissive electrode 33. In this embodiment of invention as shown in tube 75 in FIGURE lc, the fluorescent light scans diirectly the photoemissive mosaic 34e. The emission ot' photoelectrons from the photoemissive mosaic 3de produces signals in the capacitatively coupled signal plate 34a. These signals are converted into video signals in the man ner Well known in the art.

In examination of stationary objects my intrascope may be further simplified by using as a source ot' scanning light` instead of a vacuum tube 16a, a steady source of light such as an electrical bulb 74 in` combination with an oscillating mirror 73 or rotating drum as shown in FIG. lc. The oscillating mirror or drum is limited in frequency of oscillations therefore video signals produced by this device must be stored until the whole image is assembled. It is also possible to use instead of a storage tube for video signals, a receiver tube such as a kinescope having a memory screen such as dark trace screen. Also a facsimile receiver can be used for this purpose, The pick.-u up tube 75 may be also simplified by eliminating the electrode 33 as was explained above. The oscillating mirror may be mounted on a pivot and may be energized by solenoids through which the current of high frequency is flowing. One set of coils serve to move the `mirror in hori zontal axis. Another set of coils is vibrating the mirror on vertical axis. The action of both coils makes the mirror oscillate in such a manner that the light reflected oy said "mirror will scan the area on which it is projected in the same manner as the flying spot which is produced by a cathode-ray tube. The construction of `an oscillating mir-- ror is well known in the art and it is believed therefore that its further detailed description will only serve to complicate the drawings.

The electron beam 33a may be of high velocity such as used in the iconoscope type of television picloup tubes or may be of a slow velocity. ln this embodiment of my invention, I use the slow scanning electron beam. lt is to be understood however that the lfast scanning electron beam may be used in my invention as well. The electron beam 33a scanning across the charge image stored in the mosaic 34C converts said image into electrical signab1 which appear Vat the signal plate 34a. These electrical sig nals can be converted into video signals over the resisrance in the manner well known in the art. The video signals are transmitted by the flexible coaxial cable i3 from the intrascope within the examined part to the video amplifiers 43a outside of said part. The amplified signals are transmitted from the amplifiers to the viewing tube of kinescope type 37 and are reconstructed therein into the visible image representing the image of the examined part. The viewing tube may be of kinescope type and does not `have to be described in detail as it is wel] known in the art. The examined part will appear on the fluorescent screen 37a of the viewing tube Ywhere it can be inspected by many examiners. Transmission ofthe image from the amplifier 43er to the viewing tube can be done by coaxial cable 43 or by high frequency waves. The image can be sent therefore not only to the immediate, but also to the remote receivers or .may be transmitted to multiple independent viewing tubes for the benet of many examiners which was one of the objectives of this invention. The image on the viewing tube 37 may also be photographed simultaneously with the intrascope examination in order to make a permanent record which was another purpose of this invention.

The contrast of the reproduced image may be changed, diminished or increased according to the needs of particular examination by using amplifiers provided with variable mu tubes, or by the use of kinescope in which gamma can be controlled. The signal to noise ratio off this system and therefore the definition of the reproduced image may be improved by using in amplifiers discriminating circuits -which reject signals below the predetermined amplitude and eliminate therefore most of the noise signals. The coaxial cable 43 'within the examined part may be encased in the above described means 26 or 26a for inserting the intrascope or may be attached to them.

The voltages for the operation of the tubes 16d and b are supplied through the flexible elastical wires 8a from the source of the electrical power 9 outside of the examined part. In the same way the horizontal and vertical synchonizing circuits, focusing fields and deflecting circuits are supplied with electrical energy from the outside source of power 9, The synchronizing and defiecting circuits and focusing fields are not described in detail as they are well known in the art and it is believed they would only complicate the drawings. In some cases the coaxial cable 43 may be outside of said inserting means 26 or 26a,

The housing 14 containing the television camera can be rotated in its position in the intrascope, so that the optical system 15 can be made to face the window -18 or 18a and to see thereby various areas of the circumference of the examined pant. The rotation of the camera can be accomplished by means of a pusher 15a which fits into extensions 10b of the box 14. The rotation of the camera may be preferable in some cases to the rotation of the whole intrascope which allows to accomplish the salme purpose.

The main rigid portion of the flexible intrascope is the ltelevision camera 16. Therefore the shorter the television camera is, the easier it will be for the intrascope to pass through sharply angulated or cunved passages. One of the advantages of the novel pick-up tube 16 is that it makes it possible to break up the smallest pick-up -tu'be into two component parts such as tubes 16a and 16h and introduce each of said tu-bes into the examined part separately, reducing thereby considerably the rigid portion of the intrascope which is due to the television camera, as shown in FIGURE la.

To accomplish these objectives the flexible intrascope lla is introduced lfirst into the examined part while containing only the box 5 housing the light source 7. Inside of the intrascope 1a, shown in FIGURE 1a proximally to the box 5 there is a ring-like partition 'which serves as a stop 27 for the pick-up tube 16h which is to be introduced later. It is obvious that the shape of this stop may vary. The rest of the intrascope 1a is empty. The intrascope la has been introduced into the examined part. As the only rigid part of the intrascope is now 'the box 5 which is very small, this intrascope can easily pass even through very narrow and curved passages. After the intrascope 1a has been introduced into the examined part for a desired distance which can be read easily on the markings provided on the outside wall of the intrascope, the next step begins. Now the housing box 14b in which the vacuum pick-up tube 16h is mounted is introduced into the intrascope. The housing box 14h is pushed into the intrascope, until it reaches the stop 27, which can. be also ascertained by the X-ray control. The box 14b may be held against the stop 27 lby spring extensions 27a, as shown in FIGURE l, on said stop 27. The housing box 14h, may be pushed into its position by a flexible elastic guide 15a Iwhich is fitted into lthe proximal end of the housing box 14h. For this purpose the housing box 14b is provided with a ringlike extension 10a at its lbase which has spring-like properties. The head of the flexible pusher 15a ts into this extension and is kept in position by ita The flexible pusher 15a may also be provided with elec trical coils =6a at its distal end which is adjacent to the element to be introduced into the intrascope. The coils 6a are connected to the source of electrical power situated outside of the examined part. In this way, the head of the pusher may be given electro-magnetic properties by closing the circuit, energizing said coils 6a. The pusher 15a will be held therefore in the elements to be introduced into the intrascope, such as boxes 14a, `14h or the optical system 15, not only by the lmechanical pressure of the extensions 10a, or 10b, but by magnetic attraction as well. When the pusher 15a is to be withdrawn, the current supplying the coils 6a is shut off. To facilitate the guiding of the box 14b into the intrascope, a set of threads 86, as shown in FIGURE lb may abe used which are at at one end attached to the stop 27, and which are threaded through the perforations in the extensions `87 of the housing box 14b. After the box 14b has been introduced into its proper position in the intrascope, the pusher 15a is removed. Another set of threads 89 is attached to the extensions 88 in the housing unit 14h and serves to pull out said box 141; to the exterior of the examined part when the examination is 'finished This arrangement is shown in FIGURE 1b.

The housing box may be omitted in some cases and the tube 16b may be introduced into the intrascope withu out any housing and will be held in position by the same means as described above for holding the box y14h.

After the box 1'4b with Ithe tube 16h has been introduced, the box 14a housing the tube 16a is introduced now into the intrascope in a similar manner as was described above. Both boxes 16h and 14a have openings at their proximal and distal ends respectively, which makes it possible to bring the fluorescent screen 31 of the tube 16a in close apposition to the photoe'missive electrode 33 in the tube 1'6b. The boxes 14a and -14b are provided with mechanical means for securing a good contact of the proximal end of the tube 16b with the dis-tal end of the tube 16a. One way of providing such a contact is to make the compartment 14a fit inside of the spring-like flange 27a at the proximal end of the compartment IMb. The housing box 14a contains vacuum tube 16a which has been described above. The housing box 14a is provided with spring-like extensions 10b which serve to accomodate the head of the pushing guide 15a.

The housing box 14a is pushed into the intrascope until it reaches the position of the stop 27b. This can be also checked by the Xray control. The stop 27b is so situated that when the housing box 14a reaches it the tubes 1.6b and 16a will be in apposition to each other. In some cases flexible coils which can be converted into magnets by passing through them an alternating current 4from an outside source of electrical power may be provided on the stops 27 and 27b or at extensions 10a or 10b of the intra* scope to help the positioning of boxes 14a and 14b. In this way the rigid portion of the intrascope which has to pass through a narrow passage or acute curvature is now only a fraction of the rigid part of intrascopes which use even the smallest pick-up tube of conventional type. This represents an important improvement as it makes it possible to introduce the intrascope into parts which were not accessible previously to examination.

It should be understood that all my intrascopes can. serve for producing and transmitting color images as well. The color system may be of mechanical type such as using a color wheel, or may be of electronic type, such using an optical system to split the light image into its component colors and to project. them on television pick.m up system.

in some applications even my novel intrascopic device cannot be introduced through the narrow or angu lated passages. For such cases I vdesigned a novelcap paratus which will overcome even 180 to 360 bends in passages. FIGURE 2 shows this embodiment of my in vention. The intrascope 50 is provided with a novel image conductor Si. The image conductor 51 consists of multiple fibers of material having .a high refractive index such as quartz, rutile or special plastics. In many applications the image conductor must be flexible and easily malleable. In suchcases acrylic plastics such as Lucite or polysterenes may be used. Especially Lucite is suitable for this purpose because it causes smaller losses of conducted light than other materials. Lucite and other above mentioned materials characterized by a high. refractive index have the property of internal refiection of the light conducted by them. Such materials cannot conduct a whole image as such but they canconduct well a light signal, it means an image point. The size of the image point l found is determinedby the diameter of a single conducting fiber 52. 1n my image conductor i assembled a bundle of such fibers which form mosaic-like end-faces and which there fore can conduct plurality of image points. All these image points will reproduce at the other end-face of the image conductor the original image provided that the image conducting fibers remain in their original spatial relationship. Each fiber 52 should have, as was explained above, a di-7 ameter corresponding to the size of one image point. The diameter of 0.1 millimeter is 'well suitable for the purposes of my invention. ln order to conduct an image of an area, eg., of one square centimeter we must have many fibers S2, the number of fibers being dependent on the resolution of reproduced image that we desire. if the reso lution of the conducted image should be 4 lines per millimeter, and if the image is of one square centimeter in size, we will need 40 fibers of 0.25 millimeter in diameter, As in many examinations it is not practical to be limited to the field of l cm?, l preferably use a few hundred of such fibers combined in one image conductor, which will allow to transmit an image of a large area.

The light conducting fibers should be polished on their external surface very exactly. They may be also preferably coated with a very thin light opaque layer which should have a lower index of refraction than the light conducting fiber itself. Such coating may have a thickness of only a few microns. l found; a great improvement of flexibility of the light conductor 5l can be obtained by having the light conducting fibers 52 glued together only at their end-faces 51a and 51h.. This is a very important feature of my device because the main requirement from the light conductor 51 is its iifexibility and malleability. if the fibers 52 are glued together along their entire length the flexibility and malleability is so much reduced that it may be not possible to use it in many examinations in which the walls or passages are fragile and may be damn aged by a rigid instrument. l' found unexpectedly that having the conducting fibers 52 free along their path be tween the end-faces will not cause any deterioration of the conducted image. I found that in spite of the fact that fibers between their end surfaces were freely movable there was no blurring of the conducted image. It must be understood however that the fibers 52 at both end- :faces of the conductor 51 must rigidly maintain their spatial relationship. Another important feature of this construction is that the diameter of the light conductor Si can be now increased because no space consuming binder or glue is present between the fibers 52 except at their end-faces. Instead of using the binder at the endfaces of fibers 52, they may also be held together at their end-faces by a fine mesh screen. Each liber is threaded through one opening of said mesh screen and is being held by said screen in constant position.

lll

It may be added that snialler losses of light may be obtained if the fibers 52 are hollow inside instead of being solid. An improvement in contrast of conducted images can be obtained by coating light conducting fibers 552 with an opaque material which eliminates the leakage of light from one fiber to the adjacent one.

The number of fibers that can be used in many esami nations will be limited by the diameter of the passages through which my intrascope has to pass. As .in many sit-q uations the channel may be only l-Z cm. wide it will be impossible to use a great number of fibers. I succeeded to overcome this limitation, by using in combination the light conductor 51 with a demagnifying optical system 53. By the use of the demagnifying optical system l can reduce the examined eld to the diameter of the image conductor 5l. If the optical system will demagmfy the image five times, I can examine the field having 25 cm.2 with the image conductor having the diameter of only l cm?. This combination represents a very important fettn ture of my invention as it is not always practical or feasi-L ble to limit the examined field only to the diameter of the image conductor. Another important feature of my optical system 53 is that it allows to project the image on the end-face 51a of the light image conductor from which it can be transmitted to the other end of the conductor. If the image were projected on the side of the conductor instead of on its end-face, it would not be conducted at all. This` is accomplished by means of the gable prism 53a.

The light image conductor Slt may be introduced into examined part simultaneously with the intrascope. ln some cases it is preferable to introduce my intrascope first and then insert the image conductor 51 or 70 into intrascope. in some cases the gable prism 53a or the whole optical system 53 may be attached to the end-face 51a of the image conductor to make one unit. The novel intrascope Si) may have the same construction of other parts as was explained above and illustrated in FIGURES 1, la and 1b.

FIGURE 2 shows the novel intrascope which com" prises my novel image conductor system. The end-face 51a serves to receive the image. As was explained, above the image is projected on the end-face 51a by the optical system 53 and is at the same time demagnified `to reduce the size of the image to the` size of the cross-section of the image conductor 51. The image is conducted by the ymultiple flexible fibers 52 which form the image con ductor to the end-face' 51h. The image emerging from.` the end-face Sllb is projected by the optical system Sri on the television pick-up tube 5S. 1f necessary the opti cal system 54 may be of magnifying type to enlarge previously demagnified image of the examined part. the television pick-up tube 55 may be of the novel type tlcscribed and illustrated in FIGURES l, ltr and lb. lt should be understood however that all types ot' televi-` sion pickup tubes can betised in my intrascope in combi nation with image conductor dll. The `television picleup tube may be of conventional vacuum tube type. The television pick-up tube may be of photoemissive type. photoconductive type, or photovoltaic type. The tele vision pick-up tube may be of velocity modulation type. The television pick-up tube may use yfast or slow seanl ning electron beam. The novelty of the combination of my image conductor with my television pick-up system resides in the ability of the intrascope provided with this combination to penetrate into locations 'which were inaccessible to my television pick-up system and to trans-y mit said image from said inaccessible locations to the television pick-up tube. The television pleit-up tube can then transmit the image to the outside of the examined part by means of coaxial cablesand it can do it gardless of the distance between the television tube and the outside. Therefore the combination of the image conductor with a television tube represents an important improvement in the art of the examng recesses inaccessible to direct visualization or to conventional optical systems. It should be understood that my system will be also capable of producing color images. For this purpose the revolving color wheel 56a may be provided in front of the television camera 55. Instead of the color 'wheel an optical system may be provided which splits the image into two or three color images and projects said images on different parts of the photocathode. It should biz' understood therefore that my invention may use all types of television pick-up tubes which can produce color images.

I found that the image conductor 51 causes severe losses of light. This loss of light is dependent of the length of the image conductor, on the number of bends and angle of said bends to which. image conductor is subjected in its passage to the examined part. In some examinations the television pick-up tube cannot be activated with the amount of light available after the passage through the image conductor, because the optical system S disposed between the image conductor and the television pick-up tube causes an additional loss of 95% of useful light. In such cases I am using the embodiment of my invention shown iii FIGURES 2o or 2b. In this modification of my invention the image conductor extends through the wall 55a of the pick-up tube S5 inside of the tube. The photoelectric photocathode 56 is now deposited on the end-face 51b of the image conductor, The :ph'otocathode 56 may be of the photoemissive type as shown in FIGURE 2a or photoconductive type as shown in FIGURE 2b. In this construction the loss of light caused 'by the optical system S4 is completely eliminated which represents a thirty-fold increase in light available for the television .pick-up tube and which makes the television vpick-up tube now responsive to the image. The image conductor is cemented to the end wall 55a of the tube 55 by the vacuum type seal. In some cases it may be preferable to provide a support for the light image conductor near the face 55a of the television tube to reduce the pull of the image conductor 51 against the wall of the pick-up tube.

Another modification of my intrascope is shown in FIG-- URE 3a. In this embodiment of the invention the image conductor S1 has its end-face 51a adjacent to the distal end of the intrascope. The window 9i can be opened by mechanical means which are well known in the art and the end-face Sla of the image conductor S1 may be brought slightly forward. This will result in apposiu tion of the image conductor with the examined part. .In this embodiment of the invention the light source for illumination of the examined part may be provided at the proximal end Sib of the image conductor. The light source 7a projects the light onto mirror which has the property for partly reflecting and partly transmitL1 ting the light. Such mirrors are well known in the art and it is believed therefore that their detailed description is not necessary. The light reflected by the mirror 58 is conducted by the image conductor `Slt to theaexamined part and forms an image thereof. This light is reflected next by the examined part and returns again through the image conductor S1 to the outside. [is the mirror 58 is half-reflecting and half-transparent the image of the examined -part can pass through the mirror 58 and be focused by the optical system on the .photocathode of the television pick-up tube. n a

Another preferred embodiment of my invention is shown in FIGURE 3. The inti'ascope in this modification consists of a rigid part 2, flexible part 2a and semiflexible tip 3. The mechanical construction of these parts is the same as described above and does not have to be' ref= peated. The internal image producing and transmitting structures of the flexible part 2a are completely different. In particular the illuminating system 7 is replaced in this modification by the flying spot kinescopee The miniature flying spot kinescope 16a or 76 was shown in FIGURE l and is a vacuum tube provided with an electron gun 28 producing a fine beam of electrons 29, with circuits 30u and 30b for deliecting said electron beam in two mutually perpendicular directions and also having a screen 3l coated with a fluorescent material. The electron gun conm ssts of an electron emission source and an electron-optin cal system to focus the electrons into a fine beame The fluorescent screen of the kinescope must be of a phosphor of a very short persistence in order to obtain a good reso lution of image. ZnO phosphor has decay time ot' one microsecond and is suitable therefore for this purposeo Still better results will be obtained by applying ZnS phos-= phor and utilizing only the ultra-violet component of its fluorescent emission, which has the decay time of '1/10 microsecond. The electron beam of the kinescope has to scan the fluorescent screen in a predetermined patternc This scatiiiing motion of the electron beam is obtained by the electrostatic or magnetic fields 30a or 30h, which pro duce deflection of said beam. This scanning electron beam 28 produces a scanning light spot which illuminates 'the examined part through window 12 and produces :successive image points .of said examined part. Successive image points are admitted through window 18 into intra scope and are projected by the optical system 15 on the end-face of the image conductor 77. The image con= ductor 77 in this modification of my invention consists of a single rod of material, which is flexible and has a. high index of refraction, such as Lucite, acrylic plastics, polystyreiies or other materials. As was explained above, such materials cannot conduct an image They can con= duct a light signal only. In my novel device, the image is produced by a rapid succession of single image points, lEach image point can be conducted by the conductor '77, because it represents only one signal. Each conducted image point, after it emerges from the conductor 77, is projected on a single or plural phototubes or photocells and is converted thereby into an electrical signal, vIf "black and white image is sufficient, only one ph0to= tube 78 has to be used. The phototube converts, as was explained above, each light image point into an electri cal signal. The successive electrical signals are conducted by flexible coaxial cables 81 to the outside of the intran scope and of the examined part. These transmitted elec trical signals are next fed into appropriate receivers, such as kinescopes, facsimilefreceivers or skiatrons, known also as a dark trace tube and are reconverted into a :visible image for inspection or for photographic record= ing. In case a color image of the examined part is necesa sary, we may use two or three phototubes or photocells. The phototube '78a will serve to receive red image points; phototube 78b will serve to receive green image points, and phototube 78C will receive blue image points. A white light image point may be split into its component colors by the use of suitable optical system. Dichroic mirrors are useful for this purpose. It should be understood, however, that there are many optical means that can be used instead of said dichroic mirrors. In some' cases, it is preferable to use, instead of dichroic mirrors, the rotat= ing color disc 58a. The importance of this construction lies in the fact that I may use now one phototube or one photocell instead of three phototubes, which will marl(a edly reduce the size of the intrascope. In this modificau tion, the speed of the flying spot produced by the kinen scope 76 has to be' increased so that the whole examined area may be illuminated during the time in which one of three color filters of the disc 56 is in front of the single phototube 78. The rotating color wheel 56 lmay be set in motion by a miniature motor, such as used in electrical. wrist watches, and which may be disposed within the intrascope. In such a case, the color wheel may be mountn ed on the shaft of said motor. In some cases it is prefer= able to have the motor disposed outside of the examined part. In such event, the -motor may be connected with the rotating disc 56 by means of flexible cables or the power may be transmitted from the motor to the disc by pneumatic means or hydraulic means. The pressure lill exerted by the motor or a column of air or rluid is prepan gated by said pneumatic or hydraulic means to the disc and will cause its rotation.

The reproduction of. color images may be improved by having in front of each phototube or photocell 78a, 73h and 78C, suitable filters 79a, 7919 and 79C, which transo mit only red, green and blue light respectively.

Itv should be understood that all types of phototubes or photocells may be used for purposes of my invention. ln particular l may use phototubes of photoemissive type, of photo-couductive type or photo-voltaic type. The pho-n tocells having silicon, germanium or bismuth in combination with antimony or aluminum with antimony are 'most suitable because such photocells show high frer quency response, `'which is necessary for the operation of my device. Also modified phototransistors, which have a large photosensitive surface in eontradistinction to the conventional ones, in which the photosensitive area is very small, may be used in my irr/ention A lft may be added that when dealing with short dis tances, which do not cause a prohibitive loss of light, the light conductor 77 may extend to the outside ot' the examined part and the image then may be examined directly without the need of conversion of light image points into electrical signals, as 'was explained above and illustrated in FllGURE 3. In such cases the image points which appear successively at the end-face 7'b of the light conductor 77, may be projected by an optical lens and may be seen by the examiner directly because, due to the persistence of vision, the successive image points conducted by the conductor 77 will reproduce a total image in the retina ofthe examiner.

ln some cases the light conductor 77 does not `have `to extend to the outside of the examined part, but it may be used in combination with an optical system, which will deliver the light image from the end-ace 7T/b of the condoctor to the outside of the examined parte This arrange ment is feasible only in locations in which the course olf the examined passages between the endmface 'llb of the conductor and the outside is well known in. advance, so that a suitable optical system can be provided.

In some applications Where the distance between the examined part and the outside is small, also the image conductor which consists of plurality ot tibers conducting light may be used without a television system. This embodiment or' my invention is shown in FIGURE 4. The light image produced by the light source 7 is conducted by 'the image conductor lll to the outside 'where it can be examined visually, recorded or photographed. ln some cases the light conductor 70 does not, have to extend to the outside ot the examined part because the course of the. examined part becomes straight. ln this event it :is preferable to combine the light image conductor With an additional optical system which rvill project the image .trom the intrascope to the outside of the examined part.

Another embodiment of my invention is shown in FIGURE in lwhich the lit source is disposed outside of the examined part 'and is projected onto the end'face of the image conductor 7@ by the half-reflecting and half-1 transparent rnirror 58, as Was explained above.

The light image of the examined part which :is transl mitted by the image conductor lll to the outside in some cases may be too Weak for visual inspection and may re quire dark adaptation of the eyes. lu such cases the image will be also too Weak. for photographing. For such aminations l made a modification of my invention 'which is shown in FIGURE 6. ln this embodiment of my inm vention. 'the image conductor 70 is inserted .into vacuum tube 6u through its wall 60a. "the photocathode luil ot' the vacuum tube which may be of photoemissive type or photoconductive type is deposited on Athe end-face Elib of the image conductor. rlhe light emerging' 'from the end tace Sib can now excite the photocathode 61 as the opti` cal system is eliminated, which as Vwas explained is cansm a prohibitive loss of light. electrons emitted from the photocathode 61 are imaged by magnetic or electrom static lenses 64 and are focused on the fluorescent screen b2 disposed at the other end ol the tube and protected by the light reflecting layer 62a such as of aluminum. "lf electron image may be also intensified by accelerating lields 64. Furthermore it may be lntensilied by electrouoptical diminution which results in au increase in intern sity proportional to the square power of linear cl'ernaguiu lication.

This may be accomplished by means of electrom-rgN netc 63 or electrostatic lenses 64. The electrostatic lenses may be in the form of series of cylinders or rings utf prt@ gressively smaller diameter. They are disposed inside or' the tube and are connected to an outside source ot po-l tential. The magnetic or electromagnetic lenses may be in the form of coils surrounding the tube from outside., Such coils .may be tapered or may be in the torm of a short coil extending from some point between the photocathode 6l and the fluorescent screen u2, up to said fluorescent screen 62. The intensified image rwhich appears on. the fluorescent screen can be inspected visually by the observer directly or may be lirst magnified by au opI eye-piece 64a. The optical magnification of `the electron optically diminished image does not result in its loss ot brightness as long as said magnification docs not exceed certain limits. In this Way the intensification of the image obtained by means of electron-optical diminution is not lost although the image is magnified again optically. Therefore the image of the examined part which was too Weak for examination can now be presented with necA essary` brightness.

The use of the image tube 60` may also be necessary -When using as an image forming radiation an .invisible radiation such as ultra-violet or linfra-red. ln cases ui which the preservation of light is not critical it; may be possible to project the image emerging from end-t`ace ilb of the image conductor 7l] on the photocathode til ofthe image tube by optical means. ln cases in which the defi nition reproduced image is not important, the end-face Sib of the image conductor 71 may be attached to the end-face of the image tube to be in tight apposition to the external surface of the image tube 50. The thickness oil the -Wall of the image tube `6u which separates the eudwt'ace 51h of the image conductor trom the photocathode til will cause however a marked blurring of the image. The image tube may be also advantageously used 'within `the intra-scope on order to intensify the 'weak image. emerg ing from the end-face ot' the image conductor before it is being projected on the television picleup tube. ln this en bodiment the image tube has to be of miniature size. This can be accomplished by eliminating focusing eleci trodes and bringing the photocathode 6l very close to the fluorescent image reproducing screen El to prevent blurring of electron image.

ln some cases it is preferable to use as the light ltr or for illumination of the examined part a polarized light. The image conducted by the image conductor to the obu server is not polarized any more due to multiple rellen tions. Therefore by providing means which 'will stop the polarized light from reaching the observer ibut will transy mit the nonpolarized light, the contrast of the examined. part will be markedly improved. This construction ls of critical importance, in devices in which the light i'or illumination. of the examined part has to be delivered to the examined part by the same image conductor which serves to return the image to the observer. There are :many ways in the art to eliminate the polarized light., FIGURE 5 shows one of the means suitable For the por pose of this invention. The rotating prism 59 serves to stop the polarized light from the source `lid and it 4will at the same time transmit the nonpolarized light. 'l'he re.. sulting improvement in contrast will make my device op erative in many cases 1n which Without this irnprovcumut it would not be feasible to examine the received image.

it should be clearly understood that all my intrascopes can Serve and produce and transmit color images as well.

It is also to be understood that in some applications the encasing means for the image conductor or for pick;E up tubes may be omitted..

My invention is not limited to visible light images, .All my intrascopes may be made responsive to invisible imq ages on either side of visible spectrum by using appropriu late photosensitive layer in the photocathode of rthe teleu vision picloup tube, It is to be understood that all my intrascopes :may serve Ifor receiving images formed not only by various electromagnetic radiations such as ultraq violet, infrared, etc but also by particles radiation such as neutrons, alphanparticies, protons, electrons or by ions, in such cases the photocathode of the pioloup tube deu scribed above may be provided with an atomic particles sensitive phosphor on the side facing said image, or may have a special electron or other atomic particles emissive photocathode,

The embodiment. of my invention illustrated in 'JBIGn URE may be `also modied by using instead of the image conductor 70, which consists of plural fibers S2, the conductor 77, which consists of one solid rod of material conducting light, as was explained above, In order to make this 4modification operative, I found that the source of light must be able to produce a scanning light illumination. Therefore, instead of the electrical bulb 65 I am using in this embodiment of my invern4 tion the flying spot of light produced by a vacuum tube 16a or 76, as was described above, The remaining parts of my device may be the same as shown in FIGURE. 5,

It is evident that in all embodiments instead of the lamp 7 or 7o, the flying spot tube in or :lo may be used as well,

l also found that the novel image conductors Sl, '78 or 77 ymay transmit not only white light but also infra= red light and ultra-violet light, It is to be understood therefore that the term light as used in my disclosure embraces the visible light as well as the invisible,

lt should be understood that in all embodiments oi invention the source of image forming radiation disposed outside of the examined body and projected into the examined body by a. suitable optical system or by light conductors described above,

Another important discovery' was that supersonic waves can be also conducted by the conductors S1, itl or 77, By using las `a source of image lforming radiation piezoelectric or ymagnetostrictive means, we may produce super-= sonic images of the examined part, Piezoelectric means may be in the lform of oscillating crystals or" quartz, titanate compounds, Rochelle salts and other similar man ieri-als,

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawings is 'to be interpreted as illus= trative and not in a. limiting sense,

l claimt A device for transporting radiation comprising at least one elongated hollow member, said member con taining an empty passage extending along the entire length of said member, said passage being surrounded by walls of said member along its entire length, said walls coma prisin-g material of a. high index of refraction, Said walls of sai-d member provided with their own coating means comprising material of a lower index of refraction than said walls, said member furthermore having the length. larger' than its diameter, and means receiving said trans= ported radiation.

2, A device as defined in claim 1 which comprises photoelectric means mounted in cooperative relationship with said mem-ber,

3. A device as defined in claim 2, in which said photon electric means are o'f solid-state type,

4. A. device as defined in claim 1 in which said metn= ber has diameter not exceeding 0,25 millimeter,

S. A device as defined in claim 1 which comprises in addition means for producing said radiation,

6, A. device as defined in claim l which comprises plurality of said members,

'7. A. device as defined in claimv `d, in which essen= tially each of said members is provided with said own coating means,

8. A device as defined in claim 6 in which the end= .face of said members is mounted in a vacuum. tube,

9. A device as defined in claim 8, which comprises in addition means for producing a beam of electrons,

10. A device as defined in claim 9 which comprises in addition means for producing said radiation,

11. A. device comprising an array of individual elonu gated hollow members Ifor transporting radiation, essere' tially each of said members containing an empty passage extending along the entire length of said members and surrounded by said walls along its entire length in rwhich said walls comprise an electrically semiconducting terial, said members mounted in parallel relationship with each other and in contiguous relationship with each other to form said array, said members having the length larger than their diameter, said members furthermore having their ends mounted in the same spatial relationshipto each other at each end-face of said array, whereby the pattern of said transported radiation is preserved,

12. A device as defined in claim 1l. in 'which members are provided with their own individual. coating means mounted on their external surface,

13, .A device as defined in claim 1l. in which walls of said members comprise light opaque means,

14, A device as ydefined in claim 11 which. comprises in addition photoelectric means mounted in cooperative relationship with said members and in which the enddace of said members is mounted in. a vacuum tube,

l5, A device as defined in claim 1l in which walls o said members comprise a material of a high dex of refraction,

16. A device as defined in claim 'il in said members have diameter not exceeding 0,25 millimeter and. in which said walls have said electrically semiconducting material at least in the major part of their length,

17', A device as defined in claim 1l which `has end-face face mounted in a vacuum tube Iarid whit in cooperative relationship with means producing radiation,

References Cited UNITED STATES PATENTS 3,021,834 2/1962, sheiaon sis-65X AMES W, LAWRENCE, Primary Examiner,

' V. LAFRANCH, Assistant Examiner, 

